[phpBB Debug] PHP Notice: in file /forums/calendar.php on line 20: require_once(./common.php) [function.require-once]: failed to open stream: No such file or directory

Fatal error: require_once() [function.require]: Failed opening required './common.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/hdm/public_html/forums/calendar.php on line 20